Abstract

The authors demonstrate the usage of magnetic fringe fields from nanoscale ferromagnets to locally control the spin degree of freedom in a semiconductor. Fringe fields stemming from multilayer ferromagnets induce a local, remanent out-of-plane magnetization in a ZnCdMnSe dilute magnetic semiconductorquantum well, which in turn aligns the spin of photogenerated carriers via exchange interaction. The authors achieve a local exciton spin polarization of up to at without the need of an external magnetic field. The spin polarization can be controlled in sign and magnitude via the magnetization of the ferromagnet and is observable up to .

Received 26 October 2006Accepted 02 January 2007Published online 02 February 2007

Acknowledgments:

The authors thank G. Bayreuther and Ch. Back for SQUID measurements, E. Neshataeva and F. Seifert for experimental and technical assistance, and acknowledge the financial support of the Deutsche Forschungsgemeinschaft within the priority program SPP 1133 “Ultrafast magnetization processes” and by the Sonderforschungsbereich 491.